The following patent document 1 discloses a core-molding method for manufacturing a pneumatic tire using a core. The core includes an outer surface corresponding to an inner surface of the pneumatic tire to be manufactured. In a process to form a green tire, an inner liner, a carcass ply, a bead core, a sidewall rubber, a tread rubber and the like are arranged on the outer surface of the core. Then the green tire with the core is vulcanized in a tire mold so that the green tire is not expanded in the tire mold. After vulcanization, the core is taken out by being decomposed from the vulcanized tire. In the core-molding method, since the deformation of the tire during vulcanization is small, it may provide a pneumatic tire with excellent dimension stability
FIG. 9 illustrates a partial cross-sectional view of a bead portion b of a pneumatic tire manufactured through the core-molding method. The pneumatic tire includes a carcass c including a carcass ply c1 that includes a plurality of carcass cords. The bead portion c is provided with a bead core d therein. The bead core d includes an inner core di disposed axially inward of the carcass ply c1 and an outer core do disposed axially outward of the carcass ply c1. The respective inner and outer cores di and do are configured to have a bead cord spirally wound plural times in a circumferential direction of the tire. The end of the carcass ply c1 is held between the inner core di and the outer core do.